There are a couple of places where I can imagine it might be somewhat problematic, but they don't have to do with OO at all. The things that come to mind are debugging issues, like not having the complete call stack available for inspection. I don't think this would be a terrible loss in most cases, but it seems to me that alot of Smalltalkers are accustomed to having a great deal of context information available in the debugger.
Scheme compilers typically allow you to run in "debug" mode which does not do tail call optimization.
Also the Scheme compilers that provide first-class environments detect when reflection is used and only become pessimistic in these cases. So in Scheme, use of the procedure (the-environment) will return a first class structure that has be "reified" on demand. The same could be so with Smalltalk's "thisContext" special variable.